A variety of advanced imaging devices have been developed over the years for ophthalmic imaging, diagnostics and surgery. For some applications, these imaging devices perform best when their optical axis is aligned with the optical axis of the imaged eye. Once the eye is brought into a position aligned with the optical axis of the imaging device, some devices enhance the precision of the imaging by keeping the eye essentially immobilized in this aligned position with a patient interface of an eye-docking system. The alignment of the optical axes is typically achieved by orienting the eye so that its optical axis is parallel to that of the imaging system and then docking the patient interface on the eye in a concentric manner. Therefore, as the precision of the imaging devices improves, the demand for eye-docking systems which provide more precise alignment also increases.
Achieving good alignment can be challenging, however, as without feedback and guidance systems the patient module often ends up docking to the eye in an off-center position with the eye's optical axis tilted relative to that of the imaging system.
In some systems, the operator of the imaging device can improve the alignment by adjusting the imaging system, the patient's eye, or both during the docking process. The operator can direct the docking iteratively by directing the patient verbally, manually orienting the eyeball, or adjusting portions of the imaging device, such as its objective or gantry. However, the inaccuracy of these approaches can make the docking process quite time consuming and frustrating.
In some systems, such as in some surgical systems using excimer lasers, the alignment is aided by a fixation light. The fixation light can be centered with the optical axis of the imaging system. The patient can be instructed to train his eye on the fixation light, aligning the patient's eye. However, even these fixation light systems have limitations.